(Updated) Naloxone — the drug that safely reverses the potentially fatal effects of an opioid overdose — has successfully revived more than 10,000 overdose victims since 1996, according to new data from the Centers for Disease Control and Prevention (CDC). The data come from a survey of 48 overdose-prevention programs around the country that distribute naloxone to drug users and their friends and family.

The prescription-only anti-overdose medication has long been available in hospitals and ambulances, but it wasn’t until 1996, when Dan Bigg, founder of the Chicago Recovery Alliance, suggested dispensing it directly to people at risk of overdose that naloxone became more widely available in the community.

Still, only 15 states and the District of Columbia are currently known to have naloxone-distribution programs, which train people to identify the signs of overdose and provide naloxone to drug users and their loved ones so that it can be used in time to save a life — even before an ambulance arrives.

The treatment and prevention of overdose has become increasingly important as overdose death rates have steadily risen in America. In 2008, for the first time, overdose surpassed car crashes as the leading cause of accidental death. That year, there were 36,450 overdose deaths, involving both legal and illegal drugs. About 20,000 fatal overdoses in 2008 involved prescription drugs, and in nearly three-quarters of cases, the victim had taken an opioid like Vicodin or OxyContin.

These are the overdoses that can be reversed with naloxone (Narcan), even if the user mixes the opioids with alcohol or other drugs like heroin, cocaine or the benzodiazepine Xanax. (Naloxone doesn’t help overdoses that do not include opioids, however: for example, the mix of alcohol and benzodiazepines that is believed to be responsible for singer Whitney Houston’s death.) Extrapolating from the data, 14,800 lives could have potentially been saved in 2008 if naloxone had been available to every person who overdosed on prescription opioid painkillers.

The authors of the new CDC report sent online questionnaires to 50 known naloxone-distribution programs in 15 states and D.C. Forty-eight programs responded, including those in the three states — New York, New Mexico and Massachusetts — that have programs supported by state and local government health authorities. 188 local programs are known to exist, but some pooled their data for the report.

Since 1996, the programs said they had distributed naloxone to an estimated 53,032 people, whom they also trained in recognizing and treating overdose. The programs received reports of 10,171 overdose reversals — meaning that naloxone may have saved at least 10,000 lives. Although not every overdose is fatal, the reported number is likely an underestimate of actual overdose reversals because there is no reporting requirement.

There’s reason to believe that even more lives could be saved. Research shows that most overdoses occur in the company of others and because they tend to occur over the course of hours, there is usually time to intervene if observers can recognize the symptoms and know how to help. In many cases, that means there’s also time for an ambulance to arrive, but acting sooner is better and having naloxone on hand may be crucial, since some users who witness overdose are reluctant to call 911 for fear of arrest.

According to the CDC report, 76% of states (or 19 out of 25 states) with overdose death rates above the median and nearly 70% of those (9 out of 13 states) with rates in highest quartile have no naloxone programs at all. And 44% of all naloxone programs surveyed reported difficulty obtaining the drug in the “past few months,” either because it was too expensive, because suppliers reported shortages of the drug, or because the programs could not find a doctor to write the needed prescriptions.

The shortages of naloxone are part of a larger national problem with drug supplies. In this case, the deficit is due to the fact that few companies actually make naloxone, so when one company stops or runs out, it takes time for another to fill the gap.

All of this is why doctors like Sharon Stancliff, the medical director of the Harm Reduction Coalition, which conducted the survey for the CDC report, have called for naloxone to be made available over-the-counter and distributed as widely as possible. The drug is safe and nonaddictive and it cannot be misused (indeed, it blocks the action of opioids, so it produces the opposite of a high), and so the more places it is available, the more likely that it will be within reach when needed. The possibility of a wider market would also be likely to spur more manufacturing of the drug.

“Thousands of fatal overdoses occur every year — but this report shows that we can reduce overdose deaths by giving members of the community the right information, training, and tools,” said Eliza Wheeler, a co-author of the CDC report, in a statement. “On a local, state, and national level, it is time that take-home naloxone programs are recognized a highly effective way to prevent overdose deaths. Such initiatives should be adequately funded and steps must be taken to ensure that naloxone is affordable and accessible.”

Much attention has been given to the recent rise in overdose deaths, and it has led to calls for potential solutions, such as increased crackdowns on patients and prescribing doctors, prescription-monitoring programs and drug take-back days. Surprisingly little consideration has been given to naloxone, the most direct way to prevent overdose deaths and the one tactic that does not threaten legitimate pain patients’ access to medication. Opponents of naloxone, like opponents of needle-exchange programs, believe that reducing drug-related harm will only increase drug use. The research does not find this to be the case.

This spring, the Food and Drug Administration will hold a meeting to discuss over-the-counter sales of naloxone. That’s a smart move. We require drivers and passengers to wear seat belts when they engage in the dangerous activity of driving, just in case. Why not allow similar protection of opioid users by making naloxone more widely available?

Correction [April 17, 2012]:The original version of this story misstated the number of states that currently have naloxone-distribution programs.

Szalavitz is a health writer at TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland’s Facebook page and on Twitter at @TIMEHealthland.